Light emitting diode submount with high thermal conductivity for high power operation

Abstract

This invention relates to the thermal management, extraction of light, and cost effectiveness of Light Emitting Diode, or LED, electrical circuits. An integrated circuit LED submount is described, for the packaging of high power LEDs. The LED submount provides high thermal conductivity while preserving electrical insulation. In particular, a process is described for anodizing a high thermal conductivity aluminum alloy sheet to form a porous aluminum oxide layer and a non-porous aluminum oxide layer. This anodized aluminum alloy sheet acts as a superior electrical insulator, and also provides surface morphology and mechanical properties that are useful for the fabrication of high-density and high-power multilevel electrical circuits.

1. A LED device comprising:
 a supporting structure comprising at least two different layers of anodized aluminum oxide, a porous layer, a non-porous layer and an electrically conductive layer over said porous layer; and 
 at least one LED chip bonded to said supporting structure, wherein said porous layer is formed first in an anodizing process followed by formation of said non-porous layer in a subsequent anodizing process, said at least one LED chip bonded to said electrically conductive layer, said electrically conductive layer formed by means of a lithographic process that uses a developer solution, said porous layer being resistant to said developer solution for more than 1 minute, wherein during the formation of the non-porous layer, said supporting structure is in an environment that is at a temperature that is within a range of about 50° C. to 90° C. 
 
     
     
       2. The LED device of  claim 1 , said electrically conductive layer comprising a metallic material. 
     
     
       3. The LED device of  claim 1 , further comprising at least one wire that is bonded to said electrically conductive layer and to the at least one LED chip. 
     
     
       4. The LED device of  claim 3 , said electrically conductive layer comprising a plurality of portions electrically isolated from one another to serve as an attaché pad or electrodes for the LED device. 
     
     
       5. The LED device of  claim 1 , said electrically conductive layer comprising a barrier film for reducing diffusion of impurities into portions of said electrically conductive layer. 
     
     
       6. The LED device of  claim 1 , said supporting structure further comprising a dielectric layer between the porous and non-porous layers on one side and said electrically conductive layer on the other. 
     
     
       7. The LED device of  claim 1 , said electrically conductive layer being in contact with said porous layer. 
     
     
       8. The LED device of  claim 1 , said supporting structure bonded to at least a second LED chip in addition to said at least one LED chip, said device further comprising at least one additional electrically conductive layer over said supporting structure, said electrically conductive layers being a part of a multi-level electrical circuit, said device further comprising a wire connecting said at least second LED chip to said at least one additional electrically conductive layer. 
     
     
       9. The LED device of  claim 8 , further comprising at least one dielectric layer between the electrically conductive layers. 
     
     
       10. The LED device of  claim 1 , said at least two different layers of anodized aluminum oxide having a total thickness of not less than about 1.5 microns but less than about 20 microns. 
     
     
       11. The LED device of  claim 10 , said at least two different layers of anodized aluminum oxide having an optical reflectivity of not less than about 60% of incident light. 
     
     
       12. The LED device of  claim 1 , wherein a breakdown voltage of said supporting structure is not less than about 100 volts. 
     
     
       13. The LED device of  claim 1 , wherein said at least two different layers of anodized aluminum oxide have a curved or angular shape. 
     
     
       14. The LED device of  claim 1 , said supporting structure further comprising a layer of a mixture of porous anodized aluminum oxide and non-porous anodized aluminum oxide between the at least two different layers of anodized aluminum oxide, a porous layer and a non-porous layer.